PROJECT SUMMARY Preventable medical errors represent a major public health problem. To prevent future errors, improve disclosure, and mitigate malpractice risks, organizations have adopted strategies for early transparent communication and emphasized quality improvement through peer review. These principles are incorporated into the AHRQ Communication and Optimal Resolution (CANDOR) Toolkit, which facilitates 1) transparent communication, 2) error prevention, and 3) achieving optimal resolution with patients and families. What physician's should do when they discover another physician's error is less clear. Application of the CANDOR process may be particularly complex when the discovering and responsible physicians practice in different facilities. Without clear expectations or mechanisms for disclosure and feedback on the part of the discovering provider, it is uncertain to what extent and in what way these errors are being communicated with patients or responsible providers. Further, known barriers to disclosure and reporting one's own error may not be relevant or replaced by other unknown barriers when considering transparent communication regarding another physician's error. Providing a communication and resolution strategy applicable to errors discovered between physicians and facilities would help address this current blind spot in the patient safety and quality improvement movement. We will investigate these questions through a series of studies engaging stakeholders. This research will be the first to develop strategies to improve physician-to-physician communication over sensitive patient scenarios representing complex ethical and professional challenges for many physicians. Furthermore, the research project, multidisciplinary mentorship team, and unparalleled research environment are ideally suited to address the career goals and educational needs of the candidate, Lesly Dossett, MD, MPH. The proposal includes a detailed educational plan with training that will be essential for successful completion of this research and for Dr. Dossett's career development. The training includes mentored research and graduate level courses in implementation science. This career development award will lay the groundwork for Dr. Dossett to perform ongoing, innovative health services research, and to become an independent investigator.